1. Field of the Invention
The present invention relates to a camshaft of the type having a plurality of cam pieces made from a sintered alloy and bonded to a steel shaft at predetermined positions by sintering.
2. Description of the Prior Art
Sintering alloy powders are molded into a green cam piece provided with a shaft-receiving bore for fitting engagement with a steel shaft. The green cam piece is kept unmoved during sintering by a positioning pin that is inserted into both the radial holes of the green cam piece and the shaft. The green cam piece with the radial hole cannot be fabricated without using a complicated and costly mold die.
It has been proposed by JP Y 62-2242 that each green cam piece is formed on its side surface with a slanting groove and kept unmoved on a steel shaft during sintering by a pin that is fitted in both the inclined hole of the shaft and in the inclined groove of the green cam piece. The proposed cam piece can be molded by a relatively simple and inexpensive die because it has no hole which crosses the shaft-receiving bore. The camshaft has cam pieces secured to the steel shaft at the respective axial positions within a desired tolerance.
However, it is somewhat costly. The disadvantage results from the a fact that the steel shaft has pin-receiving holes inclined to its axis, because the inclined holes are not easily machined without special tools.